SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '098823e32577cb31cd55b99e453a57757e5e1026781bc18d4934277f0ec26712' 
  AND token = 't52AudCCjgtvmf24TQNpRZFPkicT5MhuEtkLKDL8Q4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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