SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39895a441d053dd8d13ed7892df286951f3e78b4c5759c23b60f498f1f49963a' 
  AND token = 'qD+mPHDPNu0Xv4TRGQ5PS/PBoQZw+0AbHUUDpVGc0XM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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