SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f157ee2080a93caeb9e643cdc2d03fa4cdd4e54ddc0b8cd428bff9791c544f52' 
  AND token = 'SIaJ5FsgfOuc/jP8asWDHaS8UM3tPVYNcbBM7A6FGR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}