SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2e717c44691def8440d8b13311e799b62d293eb9956c5ba34defdc637139bc2' 
  AND token = 'uzxMIIek83yS/E/E46mVymbq082Zn4amdrH8vEDttmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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