SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75d1d4d64fedd8164499b345d2151941834fbb8ed1ab0361c7582f5260754cf5' 
  AND token = 'OOxO/JD9HlFsNFJQSCqqI3QTBsugy+ETGFN3wKI/llg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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