SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7574b748f92c83735a58a1404ee931dabf1ac0209f4faf650a4f4ddcb309a19b' 
  AND token = 'cLTwYFPiDFz70vHmBRow+/689NemBF2IQC62O2I7tQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}