SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca9def9dfee488b61ecefd8aca17109785f373bf0697f3130982479124efe036' 
  AND token = 'A+1FQNE+YAH49BLXjtTnJu2fVlFmVjxYSgsqjbO1vog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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