SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d75fef0ef5d4c3bf956bc1b7fb3cea248fb76cf1a03296e056ef6c621062607' 
  AND token = 'GfEcwdXfbP0zFysOQ1hTdfGopfT6PIUDjOvL5wKpsQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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