SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8583f1bf9dd185577033e22193f18435471722f7beda46b050abd8981dd13f95' 
  AND token = 'pvSoQzlJFMd7SBT8BIiF00isLM1sidK7boHIHV3uyoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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