SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e55184e7d64074949f807dd57bb9637f3c136255d76d9d22e10e2fcbbb895fae' 
  AND token = '/++dwT1fVR15WBcgAFLMyJNvJ2WKutmjCIDgK3XLuuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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