SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4c462b64de48881166a1311126662b2df26d15aad7d64b4600395c4fe36e995' 
  AND token = 'XcAMGyp8qhVHklzHE2MJMcvS/VwTIRWsNMbC2rSmL7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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