SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e2b9133dc96e4ca5665964ad12187d5074da6317085d09bb761c5f01c93af75' 
  AND token = 'u0xNYprc2VGbSSb/3iQ+XJNafMAYfrhIUfyOopDTEek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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