SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e549b19f0ed60296827567ede49faa4e078f445664721378adb88a5110dd0f22' 
  AND token = 'JvY6/kcLDkgzvQ/IgC6W0031NNWzb1khjWI7GZKgWKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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