SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2b2829516d47c90561424c664a290c74d5324020b9dff6587d4d3db53a451b3' 
  AND token = 'IORqlWTKlN0ohjojSO2al44ZYgAGv6UB+QXdgBlX/Ss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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