SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adccf7beabb35323abcb2830df275ed646ab965e928aa4df802998059e1d668b' 
  AND token = 'V1AfI5bwVrOi1KE6lzfGenyNmV4p4eZZDMelZL6f5p4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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