SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4afd8e2d44cb778069e57e2e16aa6e866dfb04225334dca24b1d80215c93423' 
  AND token = '/oMsYExyrpLdrSjnPGw+VcCR1vIWkbpTf+vHnJktvrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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