SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cc93af368a8126e49cb29c9bcbd710bf1082e91e3f7a118165bb76042cf3977' 
  AND token = 'PZfXOctwPwxU0+2SR1oEi1R87JCAvwhwupWrr7IMc0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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