SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e52f9830955885aa2abb42b4a099eff420ff9fd96d9ebc9a44fc857b3407bc4' 
  AND token = 'w1Ru7iRvfrq4RjhzgRjxjHlpQCA612Xsq+xLLT8dDIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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