SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a80e8222b0451963a7e88c5590ba0f731c795e000f39aed2d6a0d6f151d3f51' 
  AND token = 'am+/4+tLpHxNzA1pvrYg/RQGldrKt2rBV/vA5oj54UU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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