SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '765588d945aeb4c996192fd4fad0e0871b14f89e885731d8ebb3e9458b18afae' 
  AND token = 'c9CdpeCig0l4bAPLyPEqTV2bBg6GrEARoG4DYBYjtiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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