SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42cee7f464f56a13e7c952a631591a45ac6f3805112979d44e275163eaf11c34' 
  AND token = 'TCY205XeifjqF8kG1Vpve9g74lmpM5JWAOJGFMw4IzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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