SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9200397422d487dc47e12f145a5329bf533442dd43d2e24e31adbed9d22b3e0' 
  AND token = 'rrJWTR9H869ipBdpXCCQR1TStqaa0UrEn29lyXCfD38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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