SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '632e8d5fd53fbf8368a386440aeac890e08355735f0c02a3f8b0baac2a86b429' 
  AND token = 'o6M+duvzL5U4NAK3+o/zAauIVAD+Xkqq7sdjKZD0xUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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