SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5b562b633c19d4cfc1fec0618a0159aacd76b7263daa74923a91f8609604165' 
  AND token = 'un4GawjQN8ONHvHjMuq2ABVHHFLeLAaR8WF0cYkZaa4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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