SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7df142598b225928c874b9f3ce55edc1726776f1a72d99d241196f0f6093f096' 
  AND token = '9R4Uqf6Rz0ntuzlElQMyc+8NTkldulQYBINjikf15Vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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