SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1b2161b476966a3a723b3ff7fdc22a41310d3b66fc6b769e9283d3536833aa3' 
  AND token = 'azOPTz831ry1MSnwq7/Fe0fBqZMuBghrihBJUdg5SwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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