SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad3834fc641d76d9bce54e17c4378be103ce70887fbdf2c67cd58682ff28e032' 
  AND token = 'FSEU5yudnDT3p9BVWdZTlmugK6rxPwuWaa63Fp9L4hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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