SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58ab37c2d47d380fcecd94742624ae8f26235f2aa765e9380c4f0d3b3c17a4f9' 
  AND token = 'kMzQ2rXVOs5Qqa4+joFy+Cpj25/dE+iXyYU3dUYPEDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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