SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '755796051883e6d81ca787eac904ba691806351682208560c9804fd33dd0e7cd' 
  AND token = 'AQ/3PbAosLMXm2JbjEuVRpuuew5SEPXnD/zZSMBFiZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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