SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '987058bd38bc492401b35573f57842fa6c91da860565f5a56485f25ff35c6c97' 
  AND token = 'qDOSiFSFCOHm3BdJP2w8wSo2m2t5MR6/TNhrBWwFHww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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