SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94254c52f1c51ebc7e19ebed52ff018fe590527f01aeed3c7a7e93885ccbad97' 
  AND token = 'YVYlQTmoUMdvdT5/6fmFlIRqxv7nySTsvur272s0FME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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