SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '923e248600792dd0c54a1d15b488610eb2e649248d6a753de9ad30d3451c5e82' 
  AND token = 'wJJKOAXVy9EmEo7F5HAvXDBnS47r1vm9PPve1HN2i4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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