SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a88bab34dc8dc31a9436e6a3f112a972f146768755d753c702e7b7f40906d51c' 
  AND token = 'Z3tVvu75nKEvEXzvBgHBXNjg1pvr9Lhh7Mf/v4v4Qns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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