SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a628d2053540e9bb5470ca4dcdb5721eca1dbffbe7a390565a3ca2389f020c12' 
  AND token = '7vGv1jiJ//WFPMbOfx/qcSg0xbjWW8o3VedEzIyeZwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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