SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f06fe4e1c20dc9d6c688dc0b9afdb535677fa0265f613240159238b42fe6cb3' 
  AND token = '7HcYviTCEoWRLkrvnMI2XPRbhglAz6nNTlXmGuBscxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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